The present invention relates to a passenger-seat airbag device which is disposed in an automobile instrument panel to protect an occupant by inflating between a windshield and the occupant in a passenger seat upon an emergency such as a vehicle collision, and more specifically relates to a passenger-seat airbag device having means for restricting a final expanded shape of the airbag formed when the airbag is inflated.
In general, a passenger-seat airbag of an automobile is accommodated within a container-like retainer so as to be disposed in an instrument panel and covered with a lid (lid-like member) attached to the retainer. The retainer is provided with an inflator for generating gas to inflate the airbag.
Upon an emergency such as a vehicle collision, the passenger-seat airbag is inflated by gas from the inflator operated for injecting the gas and largely expands into a vehicle cabin by pushing and opening the lid to receive an occupant rapidly moving forwardly due to an impact of the collision, etc.
FIG. 2 is a sectional view of a conventional passenger-seat airbag 100 showing an expanded state thereof.
The passenger-seat airbag 100 has a substantially conical expanded shape tapered toward the rear end (left end viewed in FIG. 2, which is identical below) thereof. The front end (right end viewed in FIG. 2, which is identical below) of the airbag 100 opposes an occupant when the airbag 100 is inflated upon an emergency such as a vehicle collision so as to form an occupant-facing surface 102 having an area sufficient for receiving the occupant. The upper-side (upper side viewed in FIG. 2, which is identical below) face of the airbag 100 forms a windshield-facing surface 104 opposing a windshield 122 in the front of the vehicle when the airbag 100 is inflated.
The periphery of an opening 106 at the rear end of the airbag 100 is connected to the opening periphery in the front side of a container-like retainer 110. Within the retainer 110, an inflator 112 is equipped so that gas injected from the inflator 112 is introduced into the airbag 100 via these openings. The airbag 100 is folded and accommodated into the retainer 110. A lid 114 is attached to the opening of the retainer 110 and the airbag 100 is equipped in an automobile instrument panel 120.
Upon an emergency such as a vehicle collision, the airbag 100 is inflated by gas from the inflator 112 operated for injecting the gas and expands into a vehicle cabin by pushing and opening the lid 114.
The airbag 100 expanded into the vehicle cabin is largely inflated between a windshield 122 of a vehicle body and an occupant. At this time, while the occupant-facing surface 102 is inflated so as to oppose and ready to receive the occupant, the windshield-facing surface 104 is inflated along the windshield 122 so as to oppose the windshield 122. When the occupant impacts the occupant-facing surface 102 so as to urge the airbag 100, the windshield-facing surface 104 is securely held by abutting to the windshield 122 so as to securely receive the occupant.
Since such a passenger-seat airbag requires to be inflated over a wide range so as to securely receive an occupant by filling up a space among the occupant, the vehicle-body windshield, and the instrument panel, the airbag is liable to have a large capacity, so that various means have been taken in order to complete the rapid expansion of such a large-capacity airbag after the beginning of the inflating.
One of such means is to increase the output of the inflator which is a gas generator for inflating the airbag; however, because the large-capacity inflator is expensive and applying a large stress to the airbag and adapters as well, these other members also require high-strength designs, so that the large-capacity inflator is not preferable in cost and weight.
There is therefore an airbag, for example, constructed to promptly complete the expansion after the initiation of the inflation of the airbag even when using a relatively small capacity inflator by reducing the volume of the airbag by connecting between an occupant-facing surface of the airbag and the periphery of an opening for gas-introduction fixed to a retainer at the rear end of the airbag with a strap, etc., so as to restrict the inflation of the occupant-facing surface.
However, when the volume of the airbag is reduced by restricting the inflation of the occupant-facing surface so as to control the expansion of the airbag in such a manner, the distance between the occupant and the occupant-facing surface in a final expanded shape of the airbag would be increased.
It is an object of the present invention to provide a passenger-seat airbag device having a sufficient capacity for absorbing an impact when the airbag is expanded and also being capable of completing the expansion promptly without increasing the output of an inflator by solving such the problems.
A passenger-seat airbag device according to the present invention is disposed in an instrument panel, and includes an airbag, which inflates between a windshield and an occupant. In the airbag device, a concave depression which separates the airbag from the windshield is formed on a windshield-facing surface of the airbag when the airbag forms a final expanded shape.
Preferably, a passenger-seat airbag further includes an internal member connecting the windshield-facing surface to an occupant-facing surface of the airbag, wherein the internal member connects the windshield-facing surface to the occupant-facing surface such that the windshield-facing surface is separated from the windshield when the final expanded shape is formed.
According to the passenger-seat airbag device of the present invention, when an inflator for inflating the airbag is operated to inflate the airbag upon an emergency such as a vehicle collision, the occupant-facing surface of the airbag is inflated toward an occupant due to the gas pressure from the inflator while an intermediate portion of the windshield-facing surface of the airbag, which is connected to the occupant-facing surface via the internal member, is pulled by the occupant-facing surface toward the occupant, for example. Thus, the windshield-facing surface is separated from the windshield so as to sink into the airbag.
Consequently, the volume of the airbag is reduced by the amount spaced from the windshield (inwardly depressed amount) of the upper intermediate portion of the windshield-facing surface, so that the airbag of the present invention can rapidly complete the inflation even when the output of the inflator is relatively small. Also, the windshield-facing surface, which does not oppose the occupant, is depressed inside the airbag so as to reduce the volume of the airbag, and the occupant-facing surface approaches sufficiently close to the occupant upon completion of the expansion. Accordingly, the occupant is promptly received by the occupant-facing surface in the vehicle collision, so that the occupant can be protected.
In the airbag, upon completion of the expansion, the intermediate portion of the windshield-facing surface becomes a concavely depressed state inside the airbag so as to be spaced from the windshield, and the upper part of the airbag is inflated so as to oppose any of the windshield and the occupant. Therefore, even when the occupant impacts and strongly urges the airbag, the upper end of the windshield-facing surface abuts against the windshield so as to securely support the airbag, enabling to securely absorb the impact from the occupant.
In the passenger-seat airbag device according to the present invention, the internal member may not break even in a finally expanded shape to connect the windshield-facing surface and the occupant-facing surface. However, it may be designed to break or tear when the occupant impacts the inflated airbag, to thereby absorb the impact due to the breaking or tearing of the internal member.